Windows 7: Desktop heap allocation failure

I have upgraded my Vista Home Premium system to Windows 7 Home premium 64 bit.
I am getting an error logged with a ID of 243 and a description of desktop Heap allocation failure. This happens at boot thus there is no windows open other than the desktop itself. Any help would be appreciated.

The upgrade route is really not the preferred method. It leaves useless files on your system and can cause conflicts.

I'd suggest you perform a "clean" install

Yes do a backup of your docs and do a clean install.

Thanks for the help, however I spent several hours last night to do a clean install and this morning I am still getting the desktop heap allocation failure at start up. When it doesn't crash I like Win 7.

Are you having any problems accessing the Internet?

When I don't get the desktop heap allocation failure everything works fine. When it happens none of the icons on the desktop work as well as links in the start menu. This only happens at start up about 25 percent of the time but may happen two or three times in a row. Do not have a lot of windows open when it happens.

Do you have a restore point you can go back to?

[Since I have had this problem ever since I installed Win 7 I don't have a restore point where the problem did not exist. I have been doing a little investigation on the net and get the idea that Win 7 is a little more picky about memory. Would the fact that my system came with three 2 Gig sticks and a 1 Gig stick be causing any problems? If I look at my desktop heap size in the registry by doing the following I wonder if the size is correct with the second number being so large.
desktop heap
If I go to the registry key
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\SubSystems\Windows
My Desktop heap size is:
ObjectDirectory=\Windows SharedSection=1024,20480,768 Windows=On SubSystemType=Windows ServerDll=basesrv,1 ServerDll=winsrv:UserServerDllInitialization,3 ServerDll=winsrv:ConServerDllInitialization,2 ServerDll=sxssrv,4 ProfileControl=Off MaxRequestThreads=16
Anyone make sense out of this info?

I know most of the registry like the back of my hand, but the CurrentControlSet is dangerous to mess around with

I am thinking now that my desktop heap allocation failures are related to my Graphics drivers for my NVIDIA Geforce 6150 SE on board graphics.
If I attempt to install the latest drivers from either the NVIDIA or HP web sites I get an increase in this Desktop Heap Allocation Failures. Roll back the drivers and I go back to the rate I am getting failures before updating the graphics drivers.
Is there a better source for drivers for this Graphics card?
I do have an available Express X16 slot but HP made the great choice of only including a 250 watt power supply which I believe will not support a graphics card being installed.
Any ideas would be appreciated.